Method and apparatus for coating pipes



Jan- 10, 193 J. B. w. GARDINER I METHOD AND APPARATUS FOR COATING PIPES Filed June '5, 1931 I5 Sheets-Sheet 1 am 8 W lEiVENTOR Jan. 10, 1933. .1. B. w. GARDINER METHOD AND APPARATUS FOR COATING PIPES Filed June 5, 1931 3 Sheets-Sheet 2 M UKM ATTORNEYS- Jan. 10, 1933. .1. B. w. GARDINER 1,893,937

METHOD AND APPARATUS FOR COATING PIPES Filed June 5, 1931 3 Sheets-Sheet 3 VINVENTOR flaw aw 1mm 12 144 l l B m PAMM; "BUM \F MM ATTORNEYS Patented Jan. 10, 1933 JOHN B. W. GARDINER, OF NEW YORK, N. Y.

METHOD AND APPARATUS FOR COATING PIPES Application filed June 5,1931. Serial No. 542,226.

This invention relates to a method and apparatus for coatin pipes primarily 1ntended for use in the eld, and 1s a continuation in part of my earlier application Serial 5 No. 358,887, filed April 29, 1929.

Broadly speaking, the device of my invention consists of a readily portable member adapted to be placed over a section or member preferably contacts with the pipe toward one end, but toward the other end is shaped to leave a clearance around a substantial part of the circumference of the pipe. It is also essential that means be included in the device to hold it in sucha position relative to the pipe that this clearance will be maintained substantially uniform while the member is being moved longitudinally along the pipe. A hopper or other similar means is provided so that the receptacle formed by the conjoint action of my device and the pipe may, be maintained filled with a viscous coating liquid while the device is being moved along the pipe and in contact with it. Generally this device will comprise a slecvelike member adapted to go entirely around the pipe but in some instances, particularly in the case of very large pipe, it may be made to embrace less than the entire circumference. When a sleeve-like member is used it is divided longitudinally into two halves so that it may readily be clamped around the pipe.

I have found that the efliciency of the device is greatly increased if the end of the structure where the clearance is to be formed is given a generally conical shape. When this is done. and tl e tool is moved along the ipe. the inertia of the liquid and its tendency to stick to the pipe force the liquid into the gradually restricted end, compressing it more tightly about the pipe, so that a very even coating of predetermined thickness is left on the pipe. This has the added 3 advantage of permitting me to supply pins or contacts which rest against the pipe and keep the device in proper position very close to the orifice, as the compression exerted beyond these pins will cause the liquid, even though it is quite viscous, to reunite to form a continuous layer.

To make the device readily movable along the pipe, I have found it advantageous to support the structure on wheels. Such wheels will not readily turn in the thick 69 liquid and therefore, I prefer to build my structure in what may be called two parts; one, the portion which has already been described, and the other, a portion which goes 1n advance of it, carrying the wheels but' which is so protected that the liquid will not enter.

Pipes of medium size are usually welded together before the coating is applied. The welds project up from the pipe a maximum distance of about three-eighths of an inch, though usually this projection is somewhat less. In order to permit my device to be moved continuously along a line of welded pipe, I arrange the orifice end so that it can open against spring pressure when a weld is met, and also arrange the support wheels so that they will lift when a weld is encountered. In order that the weld may not tip the tool, I have found it advisable to use a relatively large number of support wheels which are spaced apart longitudinally as well as angularly around the pipe, as by this arrangement there can always be enough wheels iii contact with the pipe proper to keep the tool in its desired position. It is to be understood that when the tool goes over a weld the clearance at the orifice will be momentarily closed and the weld joint will have to be touched up by hand, but the bulk of the pipe is properly coated by the use of my tool.

In some instances pipe-lines are laid of pipe which is welded longitudinally leaving a small longitudinal ridge along the pipe. In such case it will ordinarily be found inadvisable to coat this ridge, (though it can be done by. making an appropriate notch in the discharge end of the tool) but it is preferable to arrange the lengths of pipe with these ridges towards the top and set my tool so it will just contact with these ridges. This may be done by adjusting all or a part of the clearance to equal the height of the ridges, which can readily be coated by hand after the balance of the pipe is coated. In the same way it is possible though not desirable (except under such circumstances as are hereinafter described) to locate narrow guide pins right at or behind the orifice which will leave narrow tracks in the coating, which may heal them selves if the coating does not set too rapidly, or may be touched up by hand. 7

Working with some types of coating, I have found that particular pains must be taken to get a good bond between the coating material and the pipe. In such cases it is advantageous to supply one or more conically arranged wipers which are submerged in the liquid and will force the liquid against the pipe as the tool is moved. This is particularly necessary in connection with the types of material which are applied cold, such as asphaltic emulsions or the cut-back preparations where the asphalt is softened with a solvent. It is not so essential when hot melted asphalt is applied. Further, if my device is used for applying a coating of wet cement which may be desired over the asphalt, and which in effect is a viscous liquid, this intermediate wiping will not ordinariily be essential though may be used if desire The foregoing features can readily be understood from the illustrative examples shown in the accompanying drawings in which Fig. 1 is a longitudinal section of a device primarily intended for applying cold material on the entire circumference of welded pipe; Fig. 2 is a section on line 22 of Fig. 1; Fig. 3 is a view of a portion of the orifice end with parts broken away to show details of construction; Fig. 4 is a detailed sectional'view on line 4-4 of Fig. 1; Fig. 5 is a view corresponding to Fig. 3 showing a modified form of construction; Fig. 6 is a sectional View at the orifice end showing a detail of the construction shown in. Fig. 5; Fig. 7 is a diagrammatic sectional view showing the arrangement of the support wheels; Fig. 8 is a view, from the orifice end, of a further modification in which less than the entire circumference of the pipe is embraced, and Fig. 9 is a longitudinal section on line 9-4) of Fig. 8.

Referring to Figs. 1 and 2, the structure here shown consists of a casing 10 formed of two parts which are hinged together as shown at 12 with the other edges made in an overlapped joint as shown at 14 which may be locked together in any way as by the plate 16 and screws 18. For the purposes of simplicity this casing will be referred to generally as if it were a unitary structure.

Slightly to the left of the center of the structure as shown in Fig. 1 the casing 10 is provided with a ring-like flange 20 to which is attached a wiper 22 which may be made of rubber, leather or other flexible material and which preferably is tensioned to contact with the pipe, here designated by the numeral 24. Extending upwardly in line with the flange 20 is a wall 26 whlch in the structure here shown runs entirely across the full width of the casin and this together with the side walls 28 an 30 and the other transverse wall 32 form a support to receive a rectangular hopper 34 through which material may be introduced into the device. Two 'rings 36 and 40 are provided to surround the pipe below the hopper o ning. The ring 36 is shown as perpendicular to the axis of the pipe and provided with a flexible wiper 42 which contacts with the pipe, whereas, the rin 40 is shown as set at an angle to the pipe, an carryin the wiper 43, the edge of Wh1Ch is clear of t e pipe. When the structure is in operation, these wipers will be submerged so that as the device is moved along the p1 e the viscous liquid will be forced against the pipe. Thus the wiper 42 can be said to apply a priming coat which will be backed up by the wiper 43.

Beyond the line of the wall 32 the casitgg 10 tapers down toward the pipe as indica at 44 but near the ends the casing members are shaped to form a ring 46 and a large internal groove 48. At various points about the circumference, pins 50 are positioned in the ring 46. The plns 50 are made very thin, looking in the direction alon the axis of the pipe, as shown in Fig. 3 an are beveled as shown in Fig. 1. Each of these pins is pro vided with a collar 52 having a pin 54 which moves in an appropriate slot, formed in rin 46, to prevent the pins from rotating. sprin 56 presses against collar 53 and is held down by a bushing nut 58 through which pin 50 passes with a sliding fit. A nut 60 may be used to adjust the position of pins 50 relative to the pipe 24 and I have found that these pins should be adjusted so that they will just press a ainst the surface of the pipe under the in uence of springs 56.

In the large grooves 48 of casing 10 are positioned a plurality of segmental members 62. The number of these may vary but for the purposes of illustration I here show six of them being used. Each of the se ental members 62 has its inside face shape d t o approximately continue the taper of casing 10 and each of the segmental members 62 is provided with a bolt 64 formed with a slidin through the casin 10 but provided wit a pair of nuts 66 to limit the inward movement of such bolt and to modify the clearance so as to determine the thickness of the coating to be applied. Around each bolt 64 is a spring 68 tensioning the segmental member 62 toward the pipe. Channels are formed in the sides of the segmental member 62 to receive balls 72 to reduce friction between the segmental members and the casing. If desired, flexible members 74 may be attached to the rear faces of the segmental members 62 to give a final smoothing action to the coating. Where these members are used, I prefer to have them slightly overlap as indicated in Fig. 3. Even though the members 50 are made quite thin, they will tend to leave tracks in the coating. However, due to the fact that they are spaced away from the point of smallest diameter of members 62, so that there is a contraction beyond the point of contact of these pins, members 62 will have a squeezing action on the viscous liquid which will cause these tracks to be filled and result in the formation of an even, smooth coating on the pipe.

The exact thickness of coating to be left on the pipe can be adjusted and set by the nuts 66 which will position the segmental members 62 relative to the pins 50. It will further be noted that as the tool is moved along the pipe,

if a weld is met, flexible members 22, 42 and 43 will bend and go over the weld and pins 50.

and segmental members 62 will ride radially against the tension of springs 56 and 48 so that the weld can be passed over.

To the right, or in front of the ring flange 20, casing 10 is formed as a cylindrical sleeve provided with a series of bosses 7 6 to receive the cups 78 for carrying the support wheels. Each of the cups 7 8 is provided with a pair of flanges or webs 80 extending down below the line of casing 10 and at their lower ends the flanges 80 are slotted as shown at 82 in Fig. l. A series of guide wheels 84 are each mounted on a hub 86 the ends of which slide in one of the pairs of slots 82. Likewise pivoted on each hub 86 are a pair of links 88 which together with the links 90 and the bolt 92 form a support for the wheels. As is shown in the lower right hand corner of Fig. 1 each of the links 88 is provided with a stop pin 94 and each link 90 is provided with a corresponding notch 96 to receive this pin. A spring 98 tensions the pin into the notch, holding the two pairs of links and the bolt 92 in alignment to give positive support for the wheel. Each bolt 92 is threaded into a bushing 100 which rotates freely in the cup 78 but may be locked in place by a set screw 102. By loosening the set screws 102 and rotating the bushings the wheels may be set exactly;

structure is moved along, if any pair of feeler bars 104 strikes a weld, the corresponding link 108 will break the joint between the links 90 and 88 so that these links will function as a toggle forcing the wheel away from the pipe, and causing it to move in the slot 82. As soon as the weld is passed the wheel will snap back into position under the influence of spring 98 and again will positively sup port the casing.

In order that all of the wheels 84 may not be lifted at the same time, I use a relatively large number of these wheels and position them at various points longitudinally of the pipe. Various arrangements of the wheels may be employed but I have found the ones indicated in Figs. 2 and 7 to be satisfactory. Here three wheels, including the one at the top, and two on each side of the bottom, are positioned in line immediately in front of a ring 20. For the purposes of com arison, these are designated by the letter A in Figs. 2 and 7. Next in front of these are the two outer upper wheels designated by the letter B. In front of these are the two lower outer Wheels designated by the letter C and fur thest front is the bottom wheel and the two top wheels on each side of the center which are designated by the letter D. By this arrangement when the wheels in any line are displaced by a weld there are still enough wheels in contact with the pipe to keep the casing rigidly aligned.

It will be seen that the device described is adapted to keep a section or portion of a pipe submerged in a viscous liquid even though the clearance of segmental members 62 from the pipe is ordinarily great enough so that a freely flowing liquid, like water, would readily flow through. For example, this clearance will ordinarily be adjusted to between three-sixty-fourths and one-eighth ofan inch or more. When the device is moved along the pipe the friction of the pipe and inertia of the liqu d will create sufiicient pressure to cause even a quite viscous liquid to pass through this clearance just as if it were extruded out under positive pressure, so that a very even coating is left on the pipe.

In the modification shown in Figs. 4 and 5, the casing 10, instead of having the ring 46, is provided with a series of bosses 110, one boss being provided for each segmental member 112. Segmental members 112 correspond to the segmental members 62, but in this case I subdivide the circumference into twelve of these segments instead of six. Attached to each boss by a bolt 114 is a plate 116 which carries a bushing 118 freely rotatable in the plate but controllable by a lock screw 120.

Threaded in each bushing 118 is a bolt 122 at the lower end of which the segmental memher 112 is pivoted. A spring 124 normally tensions each segmental member to the position shown in Fig. 6. As shown in Fig. 5,

ISO

segmental members 112 are cut away at their outer meeting parts so that their ends meet only for a short distance as indicated at 126. ThlS arrangement is made so that if any of the liquid from the casing moves in between the segmental members when they are opening to pass over a weld, it will not hold these members apart after the weld is passed. The posit-ion of the segmental members relative to the pipe can be adjusted by turning the bushings 118. Obviously the springs 124 are intended to be stifl' enough so that members 112 will not move under the pressure of the liquid that is being supplied but will only move when a solid obstruction is met. In other words, the members 112 may be termed substantially rigid to distinguish them from flexible wiping members which are held pressed against a plate as in the case of brushes or the like which have been used for painting and which normally are maintained in flexed position.

In Figs. 8 and 9 I show a modified form of device intended primarily for use on very large diameters of pipe. Such pipe is ordinarily coated before the lengths are connected together, and to do this the pipe is placed on a roller frame 122 provided with rollers 124. In this instance the casing 126 has no bottom half, but is provided with a bottom wall 128 on each side of the pipe which extends over toward the pipe but does not contact with it. Attached to this wall, on each side, is a flexible member 130 which wipes against the pipe to keep the liquid from flowing down around the sides of the pipe. Also in this case I have shown the orifice as not being adjustable, though either of the adjustable forms shown may be used.

This form of device will primarily be useful with melted asphalt and when working with such material it may be heated in any desired manner not shown, as by electrical resistance elements, gas burners or charcoal burners. To conserve heat, the support end of the casing 132 is made separate from the liquid receiving portion to which it is bolted with a washer of heat insulating material interposed between them. Such washer is designated by the numeral 134. In this case, a number of fixed wheels as indicated at 136 may be used to support the device at the top of the pipe, and to hold it down on the pipe I ma have arms 138 which are pivoted to the sldes of the casing carrying additional wheels 140. These arms are tensioned toward the pipe by springs 142.

In operating this form of my apparatus, it is posit oned on the pipe and the desired liquid poured in the hopper. The tool is then moved along the pipe, coating the upper surface for a substantial part of the length of the pipe. After this coating has hardened, the pipe is rotated on the rollers 124, bringing the uncoated part to the top. The tool is again placed in position, with the flexible members 130 pressing against the previously coated surface instead of against the pipe itself. A second application is then made which unites with the first application so that the entire pipe is coated. While I have found it desirable to use only two operations for coating the pipe, three or more operations may be used, reducing the angular proportion of the section of pipe which is submerged in the liquid.

As brought out, this device may be used for applying to pipes a large variety of coatings which are sufiiciently viscous so that they will stay in place on the surface of a pipe in the form of a coating of substantial thickness (as distinguished from a thin film maintained by surface tension). Further, while my device is primarily intended for use on pipes, it may be used on other related articles such as bars or rods.

What I claim is 1. In combination, a sleeve adapted to be opened along its axis and adapted to surround a portion of a pipe so that when said sleeve is around a substantially horizontal p pe, it will cooperate with the pipe to form a receptacle for a viscous liquid, an opening in the side of said sleeve through which a viscous liquid may be readily introduced, means for substantially closing one end of the sleeve around the pipe, substantially rigid means largely closing the other end of such sleeve comprising a member surrounding the pipe, but leaving a subsfantially clear circular space around the pipe, and means for supporting the sleeve on the pipe, whereby said sleeve will be maintained with such member substantially concentric with the pipe.

2. An apparatus for coating pipe which comprises a sleeve adapted to surround a section of a substantially circular pipe of predetermined radius, such sleeve having an end portion with a substantially circular orifice of a radius from about three-sixty-fourths of an inch to one-eighth of an inch greater than the radius of the pipe, means for submerging a section of the pipe withn such sleeve and immediately adjacent such orifice in a viscous liquid, and means for supporting such sleeve on a substantially horizontal pipe so as to permit movement of the sleeve longitudinally of the p'pe, such means including members adapted to contact with such pipe within such sleeve but at a point where the sleeve has a larger internal diameter than at the orifice whereby when the member is moved along the pipe and the pipe is submerged in a viscous l'quid within the sleeve, the orifice will be maintained substantially concentric with the pipe and a coating of such liquid will be squeezed through such orifice against the pipe and the pressure of such end portion against the liquid will cause the tracks of such contacting members to be covered, and a substantially uniform coating to be formed on the pipe.

3. A structure as specified in claim 2, which includes means for adjusting the diameter of such orifice.

4. A structure as specified in claim 2, in which the end portion having said orifice is divided into sections mounted to separate when pressed apart by a projection on the p A device for coating pipes and the like with viscous 1i uid which comprises a member adapted to t over a top section of a substantially horizontal pipe and with the pipe to form a receptacle to receive a viscous liquid whereby the section of pipe embraced by such member ma be submerged, such member having a su stantially rigid part converging toward the pipe at one end and said converging part being shaped to leave a clearance at its smaller end extending a substantial distance around the pipe, said clearance being of substantial width but narrow enough to hold a viscous liquid in the receptacle when such member is at rest on the pipe, such member also having an opening which will permit the ready introduction of a viscous liquid into such receptacle adjacent the enlarged end of such converging part, and means for supporting such member on the pipe so as to maintain said clearance substantially uniform as the member is drawn longitudinally along the ipe.

6. A structure as speci ed in claim 5, which also includes a second part within said member, also converging towards the pipe, and adapted to be substantially submerged by the liquid when said receptacle is filled.

7. A readily portable device for applying viscous liquids to pipes, comprising a sleeve member adapted to be fitted around a pipe and to form a substantial seal with the pi e toward one end and formed to provide a su stantially rigid member converging around the pipe towards the other end but leaving a substantial clearance substantially around the pipe at the converging end, means whereby a viscous liquid may be introduced into such member to submerge the section of pipe embraced therein and means connected with such member beyond the aforesaid seal adapted to support said member on an approx mately horizontal pipe with the opening 1n the converging end substantially concentric with the pipe, and further adapted to permit said member to be readily moved along the 1 e. p A device for applying viscous liquid to pi es, comprising a readily portable member a apted to fit over a section of an approximately horizontal pipe, and when in place on such pipe to form a receptacle adapted to hold a viscous liquid so as to cover the top of the pipe, said member having an end portion shaped to leave a clearance opening of 9. In combination with a readily portable member for coating pipes adapted to cooperate with a horizontal pipe to form a receptacle for a viscous liquid and having an opening around the pipe near one end, a

support device for such member comprising a 1 second member rigidly connected with said first member and extending along the pipe beyond said receptacle in the opposite direction from said opening, a plurality of supports carried by said second member adapted to contact with said pipe at a plurality of points spaced apart both longitudinally and angularly and means for preventing such receptacle from closing at its open end around the body of a pipe which will-pass through said supports.

10. A structure as specified in claim 9, in

which said supports are adapted normally to hold said members rigidly relative to the circumference of the'pipe but are adapted to move relative to such members when passing over projections on the surface of the pipe.

11. A structure as specified in claim 9, in

. which said supports are wheels normally held positively relative to said second member and which further includes means adapted to permit said wheels to move relative to said second member when passing over a weld.

12. A structure as specified in claim 9, in which the supports comprise toggles and which includes means for breaking such toggles as the supports approach a projection on the pipe.

13. An apparatus for coating pipe which comprises a member'having a substantially circular opening of a diameter suificiently greater than the outside of the pipe so that if such member and the pipe were held substantially concentric a freely flowing liquid would readily flow through the clearance space, means associated with such member adapted to cooperate with the pipe to form a receptacle wherein a section of the pipe immediately adjacent such member may be submerged in a liquid sufliciently viscous so that it does not flow throu h the opening between the pipe and said mem er, and means adapted to hold said member so that its opening remains substantially concentric with the pipe but adapted to permit such member to-be moved longitudinally of the pipe, whereby liquid immediately in advance of such member may be ut under pressure to force it against the PIPGB-Dd through such opemng so that a coating of definite thickness Wlll be left on the pipe.

14. An apparatus for coating pipes whlch comprises mechanism adapted to cooperate with a substantiall horizontal pipe to form a receptacle where y a section of such pipe, including the top portion, may be submerged in a substantially confined body of viscous liquid with the level of such submerging liquid above such top portion, means associated with such mechanism adapted to hold such mechanism relative to the pipe in such position that such mechanism is held spaced away from the pipe around a substantial arcuate 7 portion of the pipe with substantial clearance space between such mechanism and the pipe such that a freely flowing liquid would readily flow out through the clearance space, but a substantially viscous liquid will not flow therethrough so that if such apparatus, while confining a viscous submerging liquid, is moved in a direction longitudinal of the pipe while the level of the main body of liquid is maintained higher than the body of the pipe at the point where the pipe emerges out of the liquid, pressure will be exerted on the liquid to force through such clearance space a layer of liquid whose thickness is determined by such clearance space.

15. A device for coating pipes and the like with viscous liquid, which comprises a member adapted to fit over a section of a substantially horizontal pipe and with such a pipe to form a receptacle to receive viscous liquid whereby the section of pipe embraced by such member may be submerged, such member having a substantially rigid part converging toward the pipe at one end with a clearance at the smaller end thereof, which clearance extends a substantial distance around the pipe and is of substantial width, but narrow enough to hold a viscous liquid in the receptacle when such member is at rest on the pipe, means associated with such member whereby the receptacle formed by such member and a substantially horizontal pipe may be maintained filled with a viscous liquid which contacts with the pipe and extends up to a level substantially above the top of said clearance opening, and means for supporting such member on the pipe so as to maintain said clearance substantially uniform as the member is drawn longitudinally along the pipe. 7

16. The method of coating pipes which comprises placing a pipe substantially horizontal, submerging a section thereof including the top portion in a substantially confined body of viscous liquid so that the level of such submerging liquid is above such top portion, and so positioning the means used to confine such liquid relative to the pipe that such means is held spaced away from the i around a substantial arcuate portion 02th: pipe with substantial clearance space between such means and the pipe such that a freel flowing liquid would readily flow out throug the clearance space but the viscous liquid used will not flow therethrough, and moving the body of such liquid in a direction longitudi nally of the ipe while maintaining the level of the main ody of li uid in which the section of the pipe is su merged higher than the body of the pipe at the point where the pipe emerges out of the main body of the liquid and thereby exerting pressure on the liquid to force through such clearance space a layer of liquid whose thickness is determined by such clearance space.

17. The method of coating pipe which comprises the steps of submerging a section of a substantially inflexible pipe in a body of liquid sufficiently viscous to remain on the pipe to form a coating of substantial thickness, and forcing such body of liquid longitudinally of the pipe by a member contacting with such liquid and surrounding such plpe but with a clearance between it and the pipe while holding such member out of contact with the pipe substantially all around the pipe, and thereby putting the liquid immediately in advance of such member under pressure and forcing it against the pipe and through such clearance so that a coating of definite thickness is left on the pipe.

18. The method of coating pipe which comprises submerging a section of a pipe in a substantially confined body of viscous liquid so that an end of such pipe emerges out of the body of such liquid below the top level thereof, and positioning said pipe relative to the means used for confining such liquid so that the portion of the pipe emerging from the body of such liquid is held spaced away from such means, with a substantial clearance space between such means and the pipe such that a freely flowing liquid would readily flow out through the clearance space, but the viscous liquid used will not flow therethrough, and moving the body of said liquid in a direction longitudinally of the pipe while maintaining the level of the main body of liquid in which the pipe is submerged higher than the body of the pipe at the point where the pipe emerges out of the main body of the liquid and thereby exerting pressure on the liquid to force through such clear ance space a layer of liquid whose thickness is determined by such clearance space.

19. The method of coating pipe which comprises surrounding a section of a substantially inflexible pipe with a member having an opening substantially larger than the outside diameter of the pipe, submerging a section of the pipe immediately adjacent such member in a liquid sufliciently viscous so that it will not flow through the opening left between said member and the pipe and then moving said member, and with it the main mass of the liquid, longitudinally of the pipe while holding said member out of contact with the pipe substantially all around the pipe and so that it has its opening substantially concentric with the pipe, whereby the liquid immediately in advance of such member is put under ressure to force it against the pipe and t rough such opening, so that a coating of definite thickness is left on the pipe.

20. The method of coating pipe which comprises surrounding a section of a pipe with a member having a substantial clearance between it and the pipe, so that it does not contact with the pipe, submerging a section of the pipe immediately adjacent such member with a body of liquid which is substantially confined except for such clearance and which is sufiiciently viscous so that it will be substantially prevented from flowing through such clearance when said member is stationary relative to the pipe, and forcing the main body of the liquid longitudinally of the pipe by moving said member along the pipe with suflicient speed so that the inertia of the liquid and friction of the liquid against the pipe force a part of such liquid to pass through said clearance to form a coating for the pipe.

21. The method of coating pi e which comprises surrounding a section 0 a substantiall circular pipe with a member having a su stantially circular opening of a diameter sufiiciently greater than the outside of the pipe so that if such member and the pipe were held substantially concentric a freely flowing liquid would readily flow out through the clearance space, submer g a section of the pipe immediately a jacent such member in a liquid suificiently viscous so that it does not flow through the openin between the pipe and said member, an moving said member and with it the submerging liquid longitudinally of the pipe while holding said member so that its opening remains substantially concentric with the pipe, whereby the liquid immediately in advance of such member is put under pressure to force it against the pipe and through such opening so that a coating of definite thickness is left on the pipe.

In testimony that I claim the foregoing, I have hereuntq set my hand this 14th day of May, 1931.

JOHN B. W. GARDINER. 

